The present invention relates to a lock chassis for securing a door and particularly to a lock chassis designed to move a latchbolt between an extended and a retracted position. More particularly, the present invention relates to a lock chassis wherein rotational motion of a spindle translates into linear motion of a slide, which retracts the latchbolt.
Conventional door latch mechanisms include a lock chassis which moves a latchbolt between an extended position and a retracted position. In the extended position, the latchbolt engages a hole in the doorframe and the door cannot freely open. With the latchbolt retracted, the door can be freely opened.
A typical lock chassis includes a spindle that interacts with a slide. The slide is typically slidably positioned between a chassis frame and a chassis flange coupled to the chassis frame. Further, a typical lock chassis includes a cover, which surrounds and contains the frame, the slide, and the flange. Rotation of the spindle translates into linear motion of the slide through a camming action. The slide engages the latchbolt and xe2x80x9cpullsxe2x80x9d the latchbolt out of its extended position and into its retracted position. The spindle of a typical lock chassis is coupled to a door handle or lever and is rotated when a user turns the door handle. Thus, turning the door handle draws the latchbolt out of its extended position and into its retracted position, allowing the door to be opened.
As described above, the typical lock chassis includes several parts, which necessitate several steps for assembly. Also, given the structure described above, a lateral blow to the door handle is translated through the lock chassis via the spindle. Because of this, such a blow to the door handle can cause the chassis frame to separate from both the chassis flange and the cover inside the door. In this way, access to the lock chassis can be gained from the outside of the door and the latchbolt can be retracted, thus allowing the door to be opened by an unauthorized user.
For a door latching mechanism to achieve a particular rating, industry regulations dictate that the lock chassis withstand certain lateral forces applied to the door handle. Therefore, a lock chassis which is easily assembled and which withstands certain lateral and axial forces would be welcomed by users of such a lock chassis.
According to the present invention, a lock chassis includes a chassis housing having two substantially identical housing halves. The housing halves are formed so they mate to form the housing when oriented 180xc2x0 relative to each other.
In preferred embodiments, the housing halves are formed to include sidewalls, which include a lateral face positioned to abut the opposite housing half when the housing halves are coupled together. The housing is secured by lugs that mate with pockets in the lateral face of the sidewall of the opposite housing half and screws which extend through apertures in one housing half and into threaded holes in the lateral face of the sidewall of the opposite housing half.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.